In August 2025, a customer from a Russian coal processing plant placed an order for two large Banana Screens from us. Our technical department designed the two banana screens according to the customer's requirements, based on the actual production needs and site conditions of the customer's coal processing plant. Key factors, including material characteristics, processing capacity, and screening efficiency, were taken into consideration. In response to the local climate conditions of the customer, the anti-freezing and insulation performance of the equipment was specially optimized to ensure the normal operation of the Banana Screens in low-temperature environments.

At present, the frame assembly and welding of the two large Banana Screens have been completed, and the production progress is estimated to have reached about 40%.

Working principle of Banana Screen

At the feeding end of Banana Screen, there is a sloping surface. It starts at an angle of 34°and then gradually decreases to approximately 10°at the discharge end. The screening surface adopts a zigzag line form with different inclinations. The thickness of the material layer from the feeding end to the discharge end remains unchanged. The ratio of material quantity to flow velocity on each section of the screening surface is stable, and the material layer is high, presenting a uniform state. The screening efficiency is significantly improved. Compared with the same effective area screening machine, the processing capacity is increased by 1-2 times. For materials with a high content of fine particles, especially when the proportion of the particle size in the material that is smaller than 1/2 of the grading particle size is large, Banana Screen has extremely high screening efficiency.

Parameter Study of Banana Screen

Determination of Main Parameters

The main parameters refer to the width and length of the Banana Screen screen box. Under the condition of meeting the requirements of the customer's process system, increasing the screen width is an important factor for improving the processing capacity of the equipment. According to the customer's production needs, the screen width of this screen is determined to be m; the length of the screen surface is one of the main factors affecting the process effect. According to the process requirements of the coal preparation plant, the length of the screen box of the screen machine is determined to be m.

Determination of vibration parameters

The magnitude of vibration parameters reflects the screening efficiency of the Banana Screen. It is usually determined based on theoretical analysis. The vibration intensity is generally within 4.5g. Although a higher vibration intensity is more conducive to improving process indicators, an increase in vibration intensity will inevitably lead to a significant increase in acceleration and inertial force, which will affect the lifespan of the Banana Screen.

When the material moves on the screen surface, due to the mixture of very fine media and coal slimes with a particle size less than 0.5mm, the viscosity of the material on the screen surface increases. Under a certain vibration force, the material cannot be separated from the screen surface and thrown to a certain vertical height, thereby reducing the desilting efficiency. If the vibration frequency is increased or the amplitude of the screen machine is increased, although the desilting efficiency can be improved, the service life of the vibration device's bearings will be shortened.

Screening method

The banana screen at the material inlet adopts a large inclination angle, which enables the materials to move rapidly and achieve quick stratification. This is more conducive to the screening of the materials. Since large pieces of material can pass through the steep slope relatively quickly, this earlier stratification can make the fine particles move closer to the screen surface more quickly, enhancing the screening effect. As the inclination angle of the screen surface decreases and the materials on the screen surface gradually decrease due to screening, the speed of material movement decreases, allowing the materials on the screen surface to maintain the same thickness. This facilitates the flipping and loosening of the materials, increasing the chance of screening for particles with a close gap size, thereby improving the screening efficiency and desilting efficiency of the screening machine.

The screen plate of Banana Screen

The screen plate is made of polyurethane elastomer through casting. The polyurethane elastomer has high elasticity, high wear resistance, and corrosion resistance. When subjected to the impact and friction of the materials, it can reduce wear and extend the service life. Compared with traditional metal screen plates, the polyurethane screen plate does not generate static electricity, avoiding the problem of material blockage caused by static adsorption, ensuring the smooth progress of the screening process. The installation structure of the screen plate is simple. There are no bolts between the plates, and they are fixed by the self-locking structure of the screen plate, which is convenient for quick disassembly and replacement.

The exciter of Banana Screen

The box-type exciter of Banana Screen is composed of an active shaft, a driven shaft, an eccentric block, a plug block, bearings, a gear pair, and a box. Through the synchronous reverse rotation of the double-axis eccentric block, a centrifugal inertial force is generated, and the resultant force direction forms a linear vibration trajectory, driving the screen box to achieve efficient material ejection and screening. The box is equipped with an active shaft and a driven shaft, each end of which has a pair of eccentric blocks of the same weight. The motor drives the active shaft to rotate, and through the gear pair, the driven shaft rotates relatively and synchronously. By using the centrifugal inertial force generated when the unbalanced heavy block rotates, the exciter generates directional excitation force. By adjusting the rotation speed of the eccentric block and the number and position of the counterweight plug block, the unbalanced rotational weight can be changed to adjust the magnitude of the excitation force and the working torque. The sealed box is filled with gear oil to lubricate and cool the gears and bearings, ensuring smooth transmission and reliable operation.